1. Field of the Invention
The present invention is generally related to communication systems and more particularly to a method of delivering information in a communication system.
2. Description of the Related Art
Service providers, which are entities that own, operate and control equipment constituting a communication system, are constantly searching for ways to improve the capacity of their systems. The capacity of a communication system relates to the number users that is served by a system at a particular time and/or the amount of information that can be conveyed (i.e., transmitted and/or received) over the communication system. System providers have a limited amount of available resources and therefore have to develop new techniques of using their resources in an efficient manner in order to maintain or increase their system's capacity. The resources of a communication system are the various equipment, various techniques used to operate such equipment and the different processing algorithms used in the communication system. Examples of system resources are radio transmission and reception equipment of the system, the amount of bandwidth allocated to the system and the amount of power allocated to transmitted signals. Resources such as system bandwidth and amount of power used in transmitting signals are regulated by governmental and standards organizations. Other resources such as radio equipment are relatively costly. Therefore, in many circumstances a service provider does not have the luxury of simply increasing its resources in order to increase capacity. Service providers therefore resort to searching for techniques that can be used to efficiently process certain communication signals in order to maintain or increase system capacity. In many communication systems, different types of user signals are conveyed. User signals carry user information which are distinguished from signals generated by system equipment which carry system information. User information is any type of information typically conveyed between users of a communication system. Signals that carry system information are generated by system and user equipment and are used by the system to operate and otherwise manage the communication system. User signals are generated by user equipment. An important type of user signal are voice signals which are real time signals that are sensitive to time delays or gaps that occur during their transmission. Real time signals are transmitted upon their creation; that is, as soon as the signal is created, it is transmitted. Once transmission of a real time signal has begun, the signal cannot tolerate any significant time delay in its processing other than front end delay. For example, a voice signal can be delayed prior to start of transmission (i.e., front end delay), but once transmission of such a signal has started any gap in transmission will cause the signal to become at least momentarily unintelligible. Another example of a real time signal is a live video signal, which also cannot tolerate any gap in transmission. Typically, a real time signal is formatted as a block of consecutive packets in which the packets are transmitted without any significant time gaps between them. Communication systems give real time signals priority over non-real time signals. A real time signal that has been received by system equipment has to be transmitted by such equipment within a certain time period to avoid the signal becoming unintelligible. The communication system has to have resources available to handle real time signals otherwise the received real time signals will be distorted.
When a user signal is received by system equipment, communication channels are made available for the signal to allow it to reach its destination. The system applies the rules of the protocol with which it is complying in order to allocate various resources to the arriving signal for establishing communications for that signal. A protocol is typically a set of rules defined by a standard that is applied by a communication system to operate, control or otherwise manage its equipment. Established communications refers to the system providing communication channels to allow the signal to travel from its origin to its destination. The system equipment allocate various resources (e.g., algorithms, radio equipment, portion of bandwidth, amount of transmission power) to establish the communication channels. The communication channels used to convey user signals are commonly referred to as traffic channels. Thus, traffic channels are a combination of various resources of the communication system. Signals that carry system information are transmitted (and received) over signaling channels. The signaling channels are available to a user once the user is authorized to use the system. Certain system information conveyed over the signaling channel are used by the system to establish communications (i.e., allocate resources) between users of the system. If a received user signal is a real time signal, the system has to allocate the resources (i.e., traffic channels) within a certain time period for the reasons discussed above. If the received signal is a non-real time signal, the system need not allocate resources for such a signal within any defined period of time. Due to the resource obligations of real time signals, the system's capacity is significantly dependent on its ability to properly process such signals.
As the amount of real time signals being conveyed over the system increases, the system has to be able to provide the resources to these signals without jeopardizing the processing of the non-real time signals. There will be circumstances where real time signals and non-real time signals compete for the same traffic channels. In such circumstances, the system can first allocate the traffic channels to the arriving real time signals and then allocate any remaining channels to the non-real time signals. If there are no remaining traffic channels, the non-real time signals will have to wait until such channels become available. The next available channel may still not be allocated to waiting non-real time signals because other more recent arrivals of real time signals will again be given priority. As a result, non-real time signals may incur significant delays prior to being served by the communication system and many times these non-real time signals are eventually dropped from the system. Consequently, the system capacity decreases. Alternatively, the system can simply give priority to non-real time signals over real time signals when the non-real time signals have been delayed, but it does so at the risk of losing real time signals, which would also result in a decrease of the system's capacity. Regardless of whether a system gives priority to real time signals or non-real time signals, there will be circumstances where the system's capacity will be adversely affected due to the two types of signals competing for the same resources.
What is therefore needed is a method that reduces the probability of real time signals and non-real time signals competing for the same resources in a communication system thereby allowing the system to maintain or even increase its capacity.